Zhang, the Olympic champion, regained the World Cup title he won in Paris three years ago by beating compatriot and top seed Ma Long in Duesseldorf in seven games and celebrated the tense victory by putting his foot through two boards.

The International Table Tennis Federation's (ITTF) jury docked the champion all of his prize money, but the 26-year-old reigning world champion was quick to apologise.

"I am very sorry for what I did," Zhang told the ITTF website.

"It was not acceptable behaviour and I am sorry. This was a perfect victory, I have been under a great deal of pressure, with people questioning my form."